Single-molecule detector

Abstract

A detector, for determining presence, number, length concentration, position and/or motion of at least one particle present in a fluid and having a dielectric coefficient other than a dielectric coefficient of the fluid, the detector including: (a) a capacitor, comprising a first conductive plate and a second conductive plate defining an inter-plate volume having a longitudinal axis; and (b) at least two electrical contacts, connecting each of the first and second conductive plates to a capacitance measuring device; the capacitor being characterized by at least one variable parameter so as to allow determination and/or monitoring of presence, number, length concentration, position and/or at least one motion characteristic of the at least one particle placed within the inter-plate volume of the capacitor.

What is claimed is:  
     
       1. A detector, for determining presence, number, length, concentration, position and/or motion of at least one particle present in a fluid and having a dielectric coefficient other than a dielectric coefficient of the fluid, the detector comprising: 
       (a) a capacitor, comprising a first conductive plate and a second conductive plate defining an inter-plate volume having a longitudinal axis; and  
       (b) at least two electrical contacts, connecting each of said first and second conductive plates to a capacitance measuring device;  
       said capacitor being characterized by at least one variable parameter so as to allow determination and/or monitoring of presence, number or concentration of the at least one particle, and at least one additional quantity of the at least one particle, said at least one additional quantity being selected from the group consisting of length, position and at least one motion characteristic of the at least one particle placed within said inter-plate volume of said capacitor.  
     
     
       2. The detector of  claim 1 , wherein the at least one particle is dissolved in the fluid. 
     
     
       3. The detector of  claim 1 , wherein the at least one particle is dispersed in the fluid. 
     
     
       4. The detector of  claim 1 , wherein said capacitance measuring device is selected from the group consisting of a capacitance meter and a capacitance bridge. 
     
     
       5. The detector of  claim 1 , wherein said at least one variable parameter is selected from the group consisting of a variable dielectric coefficient and a variable cross-sectional area, said cross-sectional area being perpendicular to said longitudinal axis. 
     
     
       6. The detector of  claim 1 , wherein at least one of the at least one particle is self-conductive. 
     
     
       7. The detector of  claim 1 , wherein at least one of the at least one particle is linkable to at least one conductive particle. 
     
     
       8. The detector of  claim 1 , wherein the at least one particle is selected from the group consisting of a cell, a bacterium, a biological molecule, an organic molecule and a polymer. 
     
     
       9. The detector of  claim 1 , wherein said determination and/or monitoring is at a nanometer resolution. 
     
     
       10. The detector of  claim 1 , wherein said capacitance measuring device is configured and designed to allow measuring of capacitance at a 1×10 −18  F resolution. 
     
     
       11. The detector of  claim 1 , wherein said determination and/or monitoring is in a sub-microsecond time scales. 
     
     
       12. The detector of  claim 1 , wherein said capacitance measuring device is, operable to measure a time dependence of a change in capacitance. 
     
     
       13. The detector of  claim 1 , wherein said first and second conductive plates engage opposite inner-faces of a capillary. 
     
     
       14. The detector of  claim 1 , wherein said first and second conductive plates engage opposite outer-faces of a capillary. 
     
     
       15. The detector of  claim 1 , wherein said capillary has a profile selected from the group consisting of a polygonal profile a circular profile an ellipsoidal profile and an irregular pattern profile. 
     
     
       16. The detector of  claim 13 , wherein said capillary is characterized by a variable cross section at any position along said longitudinal axis. 
     
     
       17. The detector of  claim 1 , wherein a transverse dimension of said first and said second conductive plates, with respect to said longitudinal axis, is constant along said longitudinal axis. 
     
     
       18. The detector of  claim 1 , wherein a transverse dimension of said first and said second conductive plates, with respect to said longitudinal axis varies along said longitudinal axis. 
     
     
       19. The detector of  claim 1 , wherein said at least one motion characteristic is selected from the group consisting of a velocity and an acceleration. 
     
     
       20. The detector of  claim 1 , further comprising at least one additional conductive layer interposted between said first and said second conductive layers, said at least one additional conductive layer having a surface area substantially smaller than a surface area of both said first and said second conductive layers. 
     
     
       21. The detector of  claim 20 , further comprising at least one electrical isolating layer, covering said at least one additional conductive layer. 
     
     
       22. The detector of  claim 20 , wherein at least one additional conductive layer is grounded. 
     
     
       23. The detector of  claim 20 , wherein said at least one additional conductive layer is a made of Gold. 
     
     
       24. The detector of  claim 21 , wherein said electrical isolating layer is a made of quartz. 
     
     
       25. The detector of  claim 1 , wherein said first and said second conductive plates are made of a material selected from the group consisting of Gold and Aluminium. 
     
     
       26. A motion detection method comprising placing at least one particle, present in a fluid and having a dielectric coefficient other than a dielectric coefficient of the fluid, within an inter-plate volume of a capacitor being characterized by at least one variable parameter, and determining and/or monitoring presence, number or concentration of the at least one particle, and at least one additional quantity of the at least one particle, said at least one additional quantity being selected from the group consisting of length, longitudinal position and at least one motion characteristic of said at least one particle, by determining a change in capacitance of said capacitor. 
     
     
       27. The motion detection method of  claim 26 , wherein the at least one particle is dissolved in the fluid. 
     
     
       28. The motion detection method of  claim 26 , wherein the at least one particle is dispersed in the fluid. 
     
     
       29. The motion detection method of  claim 26 , wherein said change in capacitance comprises time dependent change in capacitance. 
     
     
       30. The motion detection method of  claim 26 , wherein at least one of said at least one variable parameter is selected from the group consisting of a variable dielectric coefficient and a variable cross-sectional area, said cross-sectional area being perpendicular to a longitudinal axis defined in an inter-plate volume of said capacitor. 
     
     
       31. The motion detection method of  claim 26 , wherein each of said at least one particle is linkable to a particle selected from the group consisting of a cell, a bacterium, a biological molecule, an organic molecule and a polymer. 
     
     
       32. The motion detection method of  claim 26 , wherein said determining is at a nanometer resolution. 
     
     
       33. The motion detection method of  claim 26 , wherein said monitoring is at a sub-microsecond time scales. 
     
     
       34. The motion detection method of  claim 26 , wherein said at least one motion characteristic is selected from the group consisting of a velocity and an acceleration. 
     
     
       35. A particle presence, number, length or concentration detector comprising: 
       (a) a capacitor, comprising a first conductive plate and a second conductive plate substantially parallel to said first conductive plate, said first and second conductive plates defining an inter-plate volume having a longitudinal axis; and  
       (b) at least two electrical contacts, connecting each of said first and second conductive plates to a capacitance measuring device;  
       said capacitor being designed and constructed for allowing a determination of a presence, number or concentration of particles placed within said inter-plate volume of said capacitor, and at least one additional quantity of said particles;  
       wherein said particles are present in a fluid and having a dielectric coefficient other than a dielectric coefficient of said fluid, and further wherein said at least one additional quantity is selected from the group consisting of length, position and at least one motion characteristic of said particles.  
     
     
       36. The particles presence, number, length or concentration detector of  claim 35 , wherein said particles are dissolved in the fluid. 
     
     
       37. The particles presence, number, length or concentration detector of  claim 35 , wherein said particles are dispersed in the fluid. 
     
     
       38. The particles presence, number, length or concentration detector of  claim 35 , wherein said capacitance measuring device is selected from the group consisting of a capacitance meter and a capacitance bridge. 
     
     
       39. The particles presence, number, length or concentration detector of  claim 35 , wherein said particles are selected from the group consisting of cells, bacteria, biological molecules, organic molecules and polymers. 
     
     
       40. The particles presence, number, length or concentration detector of  claim 35 , wherein each of said particles are linkable to at least one conductive particle. 
     
     
       41. The particles presence, number, length or concentration detector of  claim 35 , wherein said particles are self-conductive. 
     
     
       42. The particles presence, number, length or concentration detector of  claim 35 , wherein said determination is at a nanometer resolution. 
     
     
       43. The particles presence, number, length or concentration detector of  claim 35 , wherein said capacitance measuring device is configured and designed to allow measuring of capacitance at a 1×10 −18  F resolution. 
     
     
       44. The particles presence, number, length or concentration detector of  claim 35 , wherein said first and second conductive plates engage opposite inner-faces of a capillary. 
     
     
       45. The particles presence, number, length or concentration detector of  claim 35 , wherein said first and second conductive plates engage opposite outer-faces of a capillary. 
     
     
       46. The particles presence, number, length or concentration detector of  claim 44 , wherein said capillary has a profile selected from the group consisting of a polygonal profile a circular profile an ellipsoidal profile and an irregular pattern profile. 
     
     
       47. The particles presence, number, length or concentration detector of  claim 35 , wherein said first and said second conductive plates are made of a material selected from the group consisting of Gold and Aluminium. 
     
     
       48. A method of determining the presence, number, length or concentration of particles present in a fluid and having a dielectric coefficient other than a dielectric coefficient of the fluid, the method comprising placing the particles and the fluid in an inter-plate volume of a parallel plates capacitor and determining the presence, number or concentration of the particles, and at least one additional quantity of the particles, by determining a change in capacitance of said parallel plates capacitor; 
       wherein said at least one additional quantity is selected from the group consisting of length, position and at least one motion characteristic of the particles.  
     
     
       49. The method of  claim 48 , wherein said particles are dissolved in the fluid. 
     
     
       50. The method of  claim 48 , wherein said particles are dispersed in the fluid. 
     
     
       51. The method of  claim 48 , wherein said particles are selected from the group consisting of a cell, a bacterium, a biological molecule, an organic molecule and a polymer. 
     
     
       52. The method of  claim 48 , wherein each of said particles is linkable to at least one conductive particle. 
     
     
       53. The method of  claim 48 , wherein said particles comprise self-conductive particles. 
     
     
       54. The method of  claim 48 , wherein said determining is at a nanometer resolution.